This will never be the strongest card in your deck, but it is surprisingly good. The value of a 2-cost Event that could do one of these things would be underwhelming, but a 2-cost Event that allows you the option to do any one of them is strong enough that it's worth considering.
Basic Spell will always be weaker than equivalent-cost aspect options, but its strength lies in its flexibility and ability to do things your aspect is bad at. Basic Spell is never a dead card; worst-case scenario, you turn it into damage to the villain. But it lets you remove threat in a pinch if you're not in Justice, heal to prevent (you or someone else!) needing to flip down to Alter-Ego if you're not in Protection, or get some extra burst damage if you're not in Aggression. Or just do more of whatever you're already going for if you don't need anything else!
Basic Spell is not an auto-include card, but it is a nice way to add some versatile burst to any Mystic deck!